Visitors tour a desalination plant in Santa Cruz. The pilot program is a joint project operated by the Santa Cruz Water Department and the Soquel Creek Water District.

Visitors tour a desalination plant in Santa Cruz. The pilot program is a joint project operated by the Santa Cruz Water Department and the Soquel Creek Water District.

Photo: Paul Chinn, The Chronicle

Image 4 of 5

A visitor examines a pressurized membrane filter displayed during a tour of a desalination plant.

A visitor examines a pressurized membrane filter displayed during a tour of a desalination plant.

Photo: Paul Chinn, The Chronicle

Image 5 of 5

Ocean water is converted into potable water at a desalination plant.

Ocean water is converted into potable water at a desalination plant.

Photo: Paul Chinn, The Chronicle

Water agencies debate desalination

1 / 5

Back to Gallery

Is it time to stick a straw into the Pacific Ocean?

About 20 water agencies up and down the California coast seem to think so.

From Marin County to San Diego, small and large projects that turn seawater into tap water are gaining favor, propelled by events unprecedented in California's history: worsening drought, dwindling species of freshwater fish, crumbling plumbing systems and unyielding demand.

Latest Living videos

But critics argue that desalination is an expensive, environmentally questionable last resort in a sprawling state that misuses one of its greatest assets.

"People are looking for an easy solution, and they look to the ocean," said Linda Sheehan, executive director of the California Coastkeeper Alliance, a watchdog group. "They're ignoring the opportunities we have for conservation, storm water reuse and water recycling."

This is not the first time the desalination debate has surfaced in California. Dry spells and government funds for infrastructure often prompt new studies and investment in the process, which strips salt, debris, bacteria and other substances from saltwater and funnels it to local taps.

But climate change, rising water costs and threats to wildlife have increased the stakes.

On a pretty stretch of beachfront at the Seymour Center at Long Marine Lab, a set of trailers holds the potential answer for the Santa Cruz area. Inside, humming pumps, pipes and tanks treat about 50 gallons of seawater a minute.

Santa Cruz and the Soquel Creek Water District hope to build a $30 million to $40 million plant that would deliver 2.5 million gallons a day to more than 130,000 customers by 2015. A plant that size would help boost supply during summer months and droughts.

"If we face a drought like the late 1970s, we could be 45 percent short of supply," Melanie Schumacher, project spokeswoman, told a group of 20 people during a public tour of the desalination apparatus on Wednesday.

Officials at the Marin Municipal Water District and the Bay Area Regional Desalination Project - comprising the San Francisco Public Utilities Commission, the East Bay Municipal Utility District, Contra Costa Water District and Santa Clara Valley Water District - make similar points about their budding plans to make saltwater drinkable.

Reservoirs for those districts - and scores of others in the state - are at critically low levels after two dry winters and possibly another one this year. Deteriorating fish populations and rules slashing the amount of water pumped through the Sacramento-San Joaquin River Delta have exacerbated the problem for most agencies.

EBMUD enacted 15 percent rationing last year, while San Francisco is contemplating similar measures depending on snow levels by the end of the water year April 1.

Conservation pushed

Water policy experts, environmentalists and consumer groups recognize the dire circumstances facing many water agencies around California. But they insist that using less water - not adding more to the supply - is the cheapest, fastest and most ecologically friendly way to stem the state's water crisis.

Desalination consumes a lot of energy, catches fish in intake machinery and flushes concentrated brine into coastal areas, and its facilities are unsightly, critics say.

Mark Massara, director of the Sierra Club's Coastal Program, said California has all the water it needs for growth projected through 2050.

"Obviously there's a need for fresh water - but there's a misperception that desalination is the Holy Grail that allows you to engage in unfettered sprawl and ignore conservation," Massara said. "Desalination is still not priced competitively with traditional water costs, and we haven't even hit the tip of the iceberg on conservation."

Research on water consumption seems to bear that out. While per-capita water use in California is decreasing, urban users could cut consumption by 2.3 million acre-feet each year - fully one-third of current urban usage - using low-tech options, said Peter Gleick, an expert on freshwater supplies.

"We should not be building desalination plants where other things make more sense," said Gleick, president of the Pacific Institute in Oakland. "At the moment a lot of other things make more sense."

Simpler alternatives

Alternatives include replacing top-loading washing machines and 3-gallon-per-flush toilets with water-efficient versions, Gleick said, while communities could offer incentives for drought-resistant plantings and use water from showers and dishwashers for irrigation.

Saving water has a price advantage. A study last year by the Los Angeles Economic Development Council found that conservation would cost $210 a year per acre-foot, compared with more than $1,000 per acre-foot for desalination.

In addition, costly amounts of energy are needed to force seawater through the fine membranes that trap tiny salt and other particles.

While the cost of desalination may grow more attractive if surface and groundwater supplies decline further and prices jump, some water experts say California's water crisis has less to do with shiny new water plants than about changing attitudes toward water.

"We need to change how we relate to water and not just dip straws into whatever water source is close by," said Coastkeeper Alliance's Sheehan. "We need to recognize the limitations to the environment and adjust our behavior. If we live in a desert climate, we need to act as though we live in a desert climate."

Latest from the SFGATE homepage:

Click below for the top news from around the Bay Area and beyond. Sign up for our newsletters to be the first to learn about breaking news and more. Go to 'Sign In' and 'Manage Profile' at the top of the page.